WILD LIFE

CHEMICAL IMMOBILIZATION OF WILD ANIMALS & ZOO ANIMALS IN INDIA

January 11, 2023

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CHEMICAL IMMOBILIZATION OF WILD ANIMALS & ZOO ANIMALS IN INDIA

The chemical immobilization of wild animals is a form of veterinary anesthesia conducted under difficult circumstances.¹Historically, chemical immobilization can be traced back to certain tribes from South America who used curare-coated arrows in their quest for food. Though this method was effective and curare derivatives were used for many years, an effort began in the late 1950s by wildlife managers in South Africa to develop new and more efficacious methods to immobilize animals for research.² Since that time, a great deal of progress has been made in developing new drugs and techniques for delivery.

Due to constant changes in restraint techniques, equipment and even immobilization drugs, wildlife veterinary practices have improved over the past decades. This progress coupled with the experience of practitioners has contributed towards a safer practice for both the animals and people involved in procedures.

The nature of wild animals dictates that any manipulation that requires handling will necessitate chemical immobilization. Anaesthetizing wild animals is typically done to mark an animal, to apply a radio transmitter, administer individual animal treatment, or for the purpose of research. Anaesthesia of wildlife can be challenging and requires that veterinarians adjust the general principles of anaesthesia to the unique anatomy and physiology of wildlife species and challenging field conditions. Specific anatomical and physiological details are not always available, although the reader is directed to excellent resources for specifics (Fowler & Cubas, 2001; Fowler & Miller, 2003). In most cases, anaesthetic protocols have been adjusted from doses in domestic species and rarely are detailed pharmacokinetic studies available. Unlike working with small animal patients, veterinarians planning to anaesthetize wildlife are not often afforded the opportunity to physically examine patients, or acquire biological samples to assess their physical status prior to anaesthesia, and that sometimes translates to choosing anaesthetic cocktails with a wider safety margin while sacrificing other parameters such as recovery time. Additionally, capture and chemical immobilization of wildlife can pose some significant human safety considerations. Lastly, morbidity and mortality of patients undergoing field anaesthetic procedures is not uncommon. For example, high ambient temperature can lead to hyperthermia.

Chemical Immobilization has become popular, safer and easier now a days in wildlife management for free ranging and captive animals.

Objective : (1) Conservation aspect (to know essential parameters for study projects i.e. blood sampling, body weight (2) Translocation of endangered species (3) For rendering treatment and surgical intervention (4) Shifting of wild animals within and outside Zoo (5) Rescue of escaped and out strayed, lost and injured wild animals (6) Transportation of wild captive animals (6) Tethering Elephant in musth.

Planning for Immobilization:

Time factor: Early morning is the best time to start the capture operation.

Understanding individual responsibility among capture team: Each member of the team should know his responsibility to avoid any misunderstanding during operation keeping in mind safety of animal as well as team members.

Proper arrangement of equipment, drug and food items: The team should have a check list of equipment, drugs and eatables.

Types of Immobilizing drugs:-

(1)Tranquilizer (2) Sedative- Hypnotics (3) Narcotics

Tranquilizer: This drug produces a calming effect and often cause in co-ordination. Tranquilizer cannot immobilize animal Tranquilizer are used in combination with narcotics to increase its potency. e.g. Acepromazine

Sedative: This group of drug causes depression of nervous system Death due to cardiac and respiratory depression in very high doses. e.g. Xylazine

Narcotics: Narcotics are powerful pain killer and C.N.S. depression in large doses. The drug should not be used to sick, stressed and exited animals which may result cardiac and respiratory depression.

Choice of drug:

Ideal drug should be selected having good safety margin, retention of reflexes, graded reversal, non- irritating to muscle, short induction time with low mortality properties.

Factors relating to non-typical reaction against standard doses:

Variation in mental calculation of the weight of the animal to be tranquilized
Age factor- Young and old animals react alike where as middle aged animals reacts differently
Time of the day- Depressants are more effective at the end of the than in the
Seasonal variations- Reaction is depend upon metabolic Metabolic rate is depending upon season of the year.
Under dosing- Little under dosing results unusual drug
Temperature of the animal- Exited animal requires more drugs for usual reactions which is unsafe for the animal.
Drug tolerance- Drug tolerance differs individual to individual and species to species.
Food- Drug absorption rate is slow in full stomach
Pathogenic condition- Sick animals reacts to drugs in unusual

Factors relating to under dosing during the time of immobilization:

The dart bounces of the animal
The dart fall from the body of the animal before entire content is
Poor targeting
Failure of syringe charge to discharge drug

Guidelines before darting animal for immobilization:

Avoid darting weak, debilated and stressed animal
Avoid immobilizing in and around water body
Immobilize during day time is best option

Avoid immobilizing in and around water body Few available imported drugs used in the field of wildlife management in India

Large Animal Immobilon Injection (10.5 ml) manufactured by Novartis, U.K. Composition: Etorphine hydrochloride (2.45 mg/ml), Acepromazine maleate (10 mg/ml)

Action: Neuroleptanalgesic; Route of administration: Intramuscular; Caution: High potency narcotic.

Large Animal Revivon Injection (10.5 ml) manufactured by Novartis, K.

Composition: Diprenorphine hydrochloride (3.26 mg/ml); Action: Immobilon antagonist; Route of administration: Intravenous.

Xylazine Injection (50 ml)

Composition: Xylazine hydrochloride (100mg/ml); Action: Analgesic, Sedative and muscle relaxant; Route of administration: i/mly

Reverzine Injection (20 ml)

Composition: Yohimbine hydrochloride (10 mg/ml); Action: Xylazine antagonist; Route of administration: i/mly or i/vly

Ketamine Injection (50 ml)

Composition: Ketamine hydrochloride (100 mg/ml); Action: Dissociate aneasthetic for single ude or combination with muscle relaxant.

Acepril Injection (10 ml)

Composition: Acepromazine maleate(10 mg/ml); Action: Tranquilizer, Preaneasthetic; Route of administration: i/mly

Brief information about two controlled drugs used in the field of Veterinary practices in wildlife management:

Etorphine hydrochloride: It is semi synthetic opiate derivative having up to 10,000 times analgesic potency of

Diprenorphine hydrochloride: It is specific drug act antagonist to Etorphine hydrochloride approved by FDA in 1973 and under control substances act of 1970.

Note:-Legal license is required to import, store and use these drugs observing multistep formalities departmentally in the state as well central Government authorities. Possession of the drug without license is offence.

Dosing of drugs:

Doses of drug vary individual to individual and species to species. Dosing of drugs to be calculated within the species but not inter species as per recommended dose.

Suggested drug and dose for large felids (Lion, Tiger and Leopard):

Xylazine @ 0.5 to 1 mg/kg B.Wt with Ketamine @ 5 to 10 mg/kg B.Wt Tentative dose of Adult Lion: 150-200 mg Xylazine with 400-650 mg Ketamine Tentative dose of Adult Tiger: 150-200 mg Xylazine with 400-600 mg Ketamine

Precautions to be taken after darting:

Whether immobilized successfully
Whether animal can be followed closely
Depth of narcosis to be observed Additional drug to be administered if required. However, it is better to avoid this practice.
Accomplishment of objectives to be completed without delay g. shifting, translocation, surgical intervention, marking/implantation of transponder, and collection of blood/tissue/hair /rectal pinch etc.

Advantages of chemical immobilization:

Selected animal can be captured
Chemical immobilization causes little disturbances to animal like fear, shock, physical damages compared to mechanical or physical
Less time
Equipments are light and handy in field

Disadvantages of chemical immobilization:

There are always undesirable side effects of Complication like cardiac arrest, pulmonary oedema, haemorrhages, hypoglycemia, brain concussion, adrenalin insufficiency, bloat, capture myopathy, shock may be noticed after minutes to hours/days after chemical immobilization.
Animal may be lost due to delay

Hand book of Chemical Capture and Restraint of wild animals

Chemical Immobilization of Wild Animals